ES2880408T3 - Method and installation for the manufacture of sand cores - Google Patents

Abstract

Method for the manufacture of sand cores, comprising a generation stage in which at least one core (9) with the desired shape is generated in an interior space (1.0) delimited by a work box (1), by manufacturing 3D in which a plurality of layers of a granulated material and an additive that solidifies the granulated material are applied alternately and selectively on a platform (1.1) of the work box (1), and a hardening stage in the that the core (9) generated in the generation stage is hardened, the generation stage being implemented with the work box (1) in a first station (101) of an installation (1000) and the hardening stage being implemented in a second station (102) of said installation (1000), transporting the work box (1) to the second station (102) where the hardening stage is implemented, after executing the generation stage in the first station (101), characterized because in stage d e hardening, to harden the core (9) generated in the generation stage, microwaves and a drying current are applied in the interior space (1.0) of the work box (1) where said core (9) is arranged, and In said hardening stage, before the application of microwaves and the drying current, the interior space (1.0) of the work box (1) is sealed at the top, with a lid (2) configured for this purpose, causing the vertical displacement of the cover (2) towards the work box (1) or of the work box (1) towards the cover (2) to carry out the tight closure, generating the drying current by applying a suction on the interior space (1.0) of the work box (1), from the outside of said interior space (1.0), said suction being applied through a suction plate (3) that is arranged between the cover (2) and the material present in the interior space (1.0) of the work box (1), and with said plate of suction (3) in contact with said material.

Description

DESCRIPTION

Method and installation for the manufacture of sand cores

TECHNICAL SECTOR

The present invention relates to methods and facilities for the manufacture of sand cores, in particular to manufacturing methods employing 3D manufacturing (also known as additive manufacturing).

PRIOR STATE OF THE ART

Sand cores are generally manufactured in a conventional sand manufacturing machine, where a mold defines the shape of the core to be manufactured in each manufacturing cycle (or of the cores to be manufactured). Subsequently, the material used to make the cores is poured into the mold, and said material hardens or cures to give solidity to the result. Said result is the sand core. The material used is a granulated material (a type of sand) mixed with at least one additive or binder (a type of resin, for example). Examples of machines where sand cores are manufactured in this way can be seen for example in EP0494762A2, and in EP2907601A1 of the Applicant himself.

In recent times, another method is beginning to be used to manufacture sand cores: 3D manufacturing (also known as additive manufacturing). In 3D manufacturing, objects (cores) are made from a granulated material (usually sand) and an additive that solidifies the granulated material, in a generation step. The granulated material and the additive are arranged in a work box, on a platform or base of the work box, by layers applied alternately and selectively, applying the additive layers only on the granulated material that interests (and which depends of the shape of the object to be manufactured). At the end of the process, the objects manufactured and solidified by the additive remain in the work box, but also the granulated material that has not been impregnated with the additive (non-solidified granulated material or excess granulated material). Therefore, it is usual to separate the objects from such excess granular material, that is, it is necessary to clean the objects.

The objects thus manufactured, although they are in a solid state, are generally fragile, and in many cases it is not possible to easily manipulate them to separate them from the excess granulated material, since the risk of breaking them is high. In this way, it is common to add a hardening stage on the objects before cleaning them, after the generation stage, to make said objects less fragile. After the hardening stage the cleaning of the objects is safer.

CN105344941A discloses a hardening step for cores made by 3D fabrication. For this, the work box is introduced into a microwave oven, and in said microwave oven the previously manufactured objects (males) are dried and hardened.

EXHIBITION OF THE INVENTION

The object of the invention is to provide a method and an installation for the manufacture of sand cores, as defined in the claims.

A first aspect of the invention relates to a method for the manufacture of sand cores. The method comprises a generation step in which at least one core with the desired shape is generated, by means of 3D manufacturing (also known as additive manufacturing). In 3D fabrication, a plurality of layers of a granular material and the material necessary to generate the core are alternately and selectively applied. In the method, said layers are applied in an interior space of a work box, on a platform of the work box.

The method further comprises a hardening step in which the core generated in the generation step is hardened, with said core arranged in the interior space of the work box. The generation stage is implemented with the working box in a first station of a facility, and the hardening stage is implemented in a second station of said facility. The working box is transported to the second station where the hardening stage is implemented, after the generation stage is executed in the first station.

In the hardening stage, to harden said core, microwaves and a drying current are applied to the interior space of the work box where said core is arranged.

The material used for the generation of males contains water, and the microwaves manage to move the particles of said water by evaporating it. The drying current, in addition to being able to contribute to said drying, drags the evaporated water that is evacuated from the environment of the males. In this way, the combination of the microwaves with the drying current implies an increase in the effectiveness of the drying of the cores and, therefore, of their hardening, thus allowing a safer cleaning later stage. In addition, this combination makes it possible to reduce the time of the hardening stage, thanks to its efficiency, which has an effect on an increase in productivity in the manufacture of cores.

In addition, in said hardening stage, before applying the microwaves and the drying current, the interior space of the work box is sealed in the upper part thereof, with a lid configured for this purpose, causing the vertical movement of the cover towards the work box or from the work box towards the cover to establish the watertight seal.

The drying current is generated by applying suction in the interior space of the work box, from the outside of said interior space and from below or from above, said suction being applied through a suction plate that is arranged between the lid and the material present in the interior space of the work box, and with said suction plate in contact with said material. The application of suction with such contact prevents the granulated material from moving in the interior space when the drying current is generated, which avoids a loss of efficiency. A second aspect of the invention relates to an installation configured for the manufacture of sand cores. The installation comprises:

- a working box where the males are generated and comprising a platform,

- a first station configured to house the work box,

- Manufacturing means that are associated with the first station and that are configured to generate the cores by 3D manufacturing in an interior space delimited by the work box, in which a plurality of layers of a granulated material and an additive that solidifies the granulated material on the platform of said working box,

- a second station configured to house the work box,

- a transport device for moving the work box from the first station to the second station, and

- hardening means that are associated with the second station and that are configured to harden said generated cores.

The curing means comprise at least one device configured to apply microwaves in the interior space delimited by the work box and a device configured to generate a drying current in said interior space.

The installation further comprises, in the second station, a cover configured to close the interior space of the work box in a watertight manner in the upper part thereof, movement means to move the cover or the work box vertically in order to establish said watertight closure and a suction plate attached to the lid with freedom of vertical movement. When the work box is in the second station, said suction plate is arranged between said lid and the platform of said work box. The current generating device is configured to apply suction into the interior space through the suction plate and the lid to generate the drying current.

The advantages that have been described for the method are also obtained with the installation.

These and other advantages and characteristics of the invention will become apparent in view of the figures and the detailed description of the invention.

DESCRIPTION OF THE DRAWINGS

Figure 1 shows in a schematic and simplified way a preferred embodiment of the installation of the invention, without some of its elements (such as a transport device, for example).

Figure 2 shows a work box with a plurality of males generated in the first station of the installation of Figure 1.

Figure 3 shows in a schematic and simplified way the first station of the installation of Figure 1.

Figure 4 shows in a schematic and simplified way the second station of the installation of figure 1. Figure 5 shows the cover of the second installation station of figure 1, providing a watertight closure of the interior space defined in the work box.

Figure 6 shows the work box of Figure 2, arranged on the structure and the cleaning platform of the second station of said installation.

Figure 7a shows in more detail the platform of the work box of Figure 2, with the holes in said platform closed.

Figure 7b shows in more detail the platform of the work box of Figure 2, with the holes in said platform open.

Figure 8 shows the work box of Figure 2, arranged on the structure and the cleaning platform of the second station of said installation, inclined.

DETAILED EXHIBITION OF THE INVENTION

A first aspect of the invention relates to a method for the manufacture of sand cores, which is implemented in an installation 1000 adapted to manufacture sand cores, as shown for example in figure 1.

In any of its embodiments, the method comprises, at least, the following stages:

- a generation stage in which the cores 9 with the desired shape are generated in an interior space 1.0 delimited by a work box 1 shown by way of example in figure 2, by means of 3D manufacturing (also known as additive manufacturing) in which alternately and selectively apply a plurality of layers of a granulated material (preferably sand) and an additive that solidifies the granulated material on a platform 1.1 of the work box 1, and

- a hardening stage in which the cores 9 generated in the generation stage are hardened. In the generation stage, a single male 9 can be generated in the working box 1, or a plurality of males 9 can be simultaneously generated in said working box 1. The generation stage is further implemented in a first station 101 of the Installation 1000, shown in Figures 1 and 3.

The work box 1 comprises the platform 1.1 and a frame 1.2, between which the interior space 1.0 is delimited. Preferably, the work box 1 is rectangular and comprises the platform 1.1 and four substantially vertical walls, the interior space 1.0 being delimited on the platform 1.1 and between the four walls.

In the hardening stage, to harden the cores 9 generated in the generation stage, without removing the cores 9 from the work box 1, microwaves and at least one drying current are applied, preferably air (although any other gaseous fluid, such as nitrogen), in the interior space 1.0 of the work box 1 where said cores 9 are located. The combination of microwaves and the drying current causes a rapid drying of said cores 9, and, therefore, its hardening. The time of application of microwaves and / or of the drying current depends on the requirements for the males 9 generated, and / or on the shape and / or total volume of the males 9 generated in the corresponding generation stage, and both procedures they can occur simultaneously or not (it depends on the requirements and the needs).

The generation stage is implemented with the work box 1, in a first station 101 of the installation 1000, shown in Figure 3 by way of example, and the hardening stage is implemented in a second station 102 of said installation 1000, shown in Figure 4 by way of example. In the method, after the generation stage is performed in the first station 101, the workbox 1 is transported to the second station 102, where said hardening stage is implemented.

During the generation stage, the granulated material and the corresponding additive are applied in the interior space 1.0 of the working box 1, on the platform 1.1, the cores 9 generated after said generation stage being, therefore, in said space interior 1.0 on the platform 1.1 of the work box 1. In the hardening stage, before the application of microwaves and the drying current, said interior space 1.0 is sealed at the top, with the cores 9 generated inside, by means of a cover 2 configured for this purpose. Thanks to the watertight closure, the microwaves and the drying current that are subsequently applied act more effectively on the cores 9. To provide the watertight closure, the vertical displacement of the lid 2 towards the work box 1 is preferably caused, until the cover 2 contacts said work box 1 (situation shown in figure 5). To ensure the watertight closure, preferably the cover 2 rests on the work box 1 (on the frame 1.2 of the work box 1), with a sealing gasket (not represented in the figures) between said frame 1.2 and said cover 2 (the sealing gasket can be attached or associated with the cover 2, for example).

In this way, it is not necessary to incorporate a microwave oven, for example, as is the case in the state of the art, and the work box 1 itself is used as a receiver for the microwaves, which results in a less expensive installation without sacrificing to the benefits of microwaves.

In the preferred embodiment, the microwaves are applied through the cover 2 by means of at least one microwave generation device 4, such as a magnetron, for example, said cover 2 comprising at least one through hole 2.0 through which the communicates the interior space 1.0 with said microwave generation device 4 and through which the microwaves are directed towards the interior space 1.0 of the work box 1. The microwave generation device 4 is connected with said through hole 2.0 in an isolated manner with the outside, that is, this communication does not interrupt the sealing provided by the cover 2 in the interior space 1.0 of the work box 1, preferably by means of a conduit 4.0, for example.

The drying current is generated by applying a suction on the interior space 1.0 of the work box 1. The suction can be caused from below (from under the platform 1.1 of the work box 1), but in a preferred embodiment it is applied from above.

In said preferred embodiment, in order to generate the drying stream, it is also necessary to have access to the outside of the work box 1, below the platform 1.1, to catch air present below the platform 1.1. In this way the platform 1.1 comprises, in at least one suction zone (not represented in the figures), a porosity that allows the passage of air through it, but not the passage of granulated material. In this way, when the suction is applied from above the interior space 1.0, air is absorbed from under the platform 1.1 through said platform, generating a drying stream from the bottom up through said interior space 1.0.

The suction is applied through a suction plate 3 that is arranged between the cover 2 and the material present in the interior space 1.0 of the work box 1, said suction being applied with said suction plate 3 in contact with said material. The fact of applying suction with said contact prevents the granulated material from moving through the interior space 1.0 when the drying current is generated, avoiding a loss of efficiency.

The suction plate 3 is connected to the cover 2 by means of a column 2.2, preferably with freedom of vertical movement. This allows that, when the lid 2 is moved to cause the sealing of the interior space 1.0 of the work box 1, if before completing this displacement the suction plate 3 contacts the material present in said interior space 1.0, said plate Suction nozzle 3 stops moving, even if cap 2 continues to move. This prevents excessive compaction of the material present in the interior space 1.0 and a breakage of the cores 9 due to this. In other embodiments the suction plate 3 is fixed to the cover 2 without freedom of movement. In these embodiments, once the interior space 1.0 of the work box 1 has been sealed, the platform 1.1 moves towards the suction plate 3 until the material present in said interior space 1.0 contacts said suction plate 3. Once said contact is achieved, said platform 1.1 is immobilized and the drying current is generated.

The area of the suction plate 3 that faces the platform 1.1 is equal to or less than the analogous area of the platform 1.1, but preferably covers at least the area of the work box 1 that houses males 9. In this way, performs a more effective suction on said cores 9, compared to a smaller area that does not cover said cores 9. Furthermore, if the suction plate 3 is to be improved even more efficiency, the suction plate 3 may comprise a chamber (not represented in the figures) along its contour, which, once the sealing occurs, is inflated or inflated with a fluid (for example, air) to fix the suction plate 3 in position with respect to the box of work 1 and to generate a tight environment between said suction plate 3 and the platform 1.1 of the work box 1 (space where the cores 9 are). The suction would be applied after the chamber is inflated.

Preferably, the suction is applied through the suction plate 3 by means of the current generation device 5 configured for this purpose (a suction pump, for example), and through the cover 2. For this the cover 2 comprises the minus one through hole 2.1 and the column 2.2 is hollow, the current generation device 5 communicating with the suction plate 3 through the through hole 2.1 and the gap of the column 2.2. Preferably, the suction plate 3 comprises, at least in a suction zone 3.0, a certain porosity that allows the passage of air through it, but not the passage of granulated material to avoid that excess or non-solidified granulated material escapes. of the space delimited between the work box 1 and the suction plate 3 through said suction plate 3 towards the current generation device 5 (which could lead to a malfunction of said current generation device 5, or even in the deterioration of said current generation device 5), applying the suction through said suction zone 3.0 (and not the rest of the suction plate 3).

Preferably, the cover 2 is made of a material adapted to withstand microwaves, such as a dielectric material or transparent to microwaves, such as Teflon or a high-density polyethylene, for example, in such a way that the energy of the microwaves are transferred to the males 9 present in the interior space 1.0 and not to the cover 2, which implies on the one hand that the cover 2 does not alter its properties and has a useful life high, and on the other hand that the lid 2 itself does not heat up and does not take energy from the microwaves, taking advantage of the highest possible energy from said microwaves for drying or hardening the cores 9. Preferably, in the same way, the work box 1 and / or the suction plate 3 are also made of a material adapted to withstand microwaves, which can be the same as the one that the work box 1 is made of.

In a preferred embodiment, the method comprises a cleaning step subsequent to the hardening step. In said cleaning stage, the excess or non-solidified granulated material that is around the cores 9 is evacuated from the work box 1. Thanks to the previous hardening stage, an effective cleaning stage is allowed without risk of the cores 9 break.

To carry out the cleaning stage, the work box 1 can be transported to a third station of the installation 1000, but in said preferred embodiment the cleaning stage is implemented in the second station 102 of the installation 1000, like the stage of hardening, which reduces process times.

In said preferred embodiment, both the microwaves and the drying current are introduced into the interior space 1.0 through the cover 2, in such a way that they do not intervene under the work box 1 and said space can be free. In this way, the evacuation of the excess material can be carried out below the work box 1, and for this the platform 1.1 of the work box 1 comprises a plurality of evacuation holes 1.1a through which the granulated material is evacuated excess or not solidified of the interior space 1.0 of the work box 1. The evacuation orifices 1.1a are closed during the generation and hardening stages, and are opened in the cleaning stage to allow the evacuation of said excess granulated material. Obviously, the size of the evacuation holes 1.1a is greater than the size of the grains of the granulated material, to enable said evacuation. Thus, said evacuation orifices 1.1a are opened in a controlled manner.

In said preferred embodiment, the second station 102 comprises a structure 102.1 and a cleaning platform 102.0 arranged on said structure 102.1 and attached to said structure 102.1, as shown in Figures 6 and 7. The cleaning platform 102.0 is a hollow frame. The work box 1 is arranged on the cleaning platform 102.0 when said work box 1 is transported to said second station 102, and is coupled to said cleaning platform 102.0. During the cleaning stage, in addition to opening the evacuation holes 1.1a of the platform 1.1, in some embodiments a controlled inclination of the cleaning platform 102.0 is caused in different directions, to cause the working box 1 to tilt in different directions. directions and thus cause a movement of the excess granulated material present in the interior space 1.0 of the work box 1, which facilitates its evacuation through the evacuation holes 1.1a (evacuation to a container 102.3 placed under the cleaning platform 102.0 , for example). To cause the inclination, a controlled movement of said cleaning platform 102.0 is generated. The cleaning platform 102.0 is supported on a plurality of support areas of the second station 102, which are movable in height, and to cause the aforementioned inclination, the controlled vertical displacement of said support areas is generated. To cause the inclination, the installation 1000 comprises a plurality of inflatable elements 102.2 in the second station 102, which are arranged between the structure 102.1 and the cleaning platform 102.0, distributed in such a way that each of them contacts a different area of the cleaning platform 102.0. Each inflatable element 102.2 comprises at least one of the support zones on which the cleaning platform 102.0 rests, and the controlled inflation and deflation of each of said inflatable elements 102.2 is caused to cause the desired inclination of the cleaning platform. 102.0 cleaning and working box 1 attached to 102.0 cleaning platform. The inflatable elements 102.2 are controlled independently, each inflatable element 102.2 preferably comprising a single respective support zone.

The cleaning platform 102.0 comprises a base with the same shape as the work box 1, which in the preferred embodiment is rectangular, thus said cleaning platform 102.0 being supported on four support zones in said preferred embodiment. Each support zone is close to, or under, one of the vertices of the cleaning platform 102.0, and to each support zone there corresponds an inflatable element 102.2 as previously described.

During the cleaning stage, the lid 2 can remain providing the watertight closure, in which case it will be attached to the cleaning platform 102.0, by means of a structure 104, to incline to the same extent as the cleaning platform 102.0, and therefore therefore, to the same extent as the work box 1, or it can be separated from the work box 1 (case in which the structure 104 is not necessary).

For cleaning, a vibration of the work box 1 can be generated, to remove the non-solidified granulated material, by itself or in combination with the inclination of said work box 1.

In examples not forming part of the invention, the drying stream is generated by an injection of air or other gaseous fluid, rather than by suction, and in other embodiments it is generated by the combination of injection and suction.

A second aspect of the invention relates to an installation 1000 configured for the manufacture of sand cores 9. Installation 1000 comprises:

- a work box 1 where the cores 9 are generated and comprising a platform 1.1,

- a first station 101 configured to receive the work box 1,

- manufacturing means that are associated with the first station 101 and that are configured to generate the cores 9 in an interior space 1.0 delimited by the work box 1, by means of 3D manufacturing in which a plurality are applied alternately and selectively of layers of a granulated material and an additive that solidifies the granulated material on the platform 1.1 of said work box 1,

- a second station 102 configured to receive the work box 1,

- a transport device (not represented in the figures) to move the work box 1 from the first station 101 to the second station 102, and

- hardening means that are associated with the second station 102 and that are configured to harden said cores 9 generated.

The first station 101 comprises at least one structure 101.1 on which the work box 1 is arranged (preferably said work box 1 is coupled to the structure 101.1). The manufacturing means associated with the first station 101 are arranged in said first station 101, said first station comprising said manufacturing means. The manufacturing means comprise at least two heads 101.2 and 101.3, a first head 101.2 that is responsible for applying the layers of granulated material, and a second head 101.3 that is responsible for applying the layers of additive. Preferably both heads 101.2 and 101.3 are freely movably attached in a horizontal direction X to a second structure 101.4 of the first station 101. The second structure 101.4 may be further comprised in the manufacturing means.

The curing means comprise at least one microwave generating device 4, and a current generating device 5 configured to generate a drying current. Both devices 4 and 5 are adapted to communicate with the interior space 1.0 of the work box 1 when said work box 1 is arranged in the second station 102.

The installation 1000 comprises, in the second station 102, a cover 2 such as the one mentioned for the method, and some movement means (not represented in the figures) to move the cover 2 towards the work box 1 or to move the storage box. work 1 towards cover 2, to carry out the watertight closure between work box 1 and cover 2. What is described for the method regarding the watertight closure is also valid for installation 1000, in any of its embodiments and / or configurations , and is not explained again for said installation 1000.

The microwave generation device 4 is further configured to direct the microwaves to the interior space 1.0 of the work box 1 through the cover 2, the cover 2 comprising at least one through hole 2.0 to enable the passage of the microwaves to its through towards the interior space 1.0 and comprising said cover 2, preferably, a material adapted to support the microwaves as described for the method. The communication between the microwave generating device 4 and the through hole 2.0 can be carried out by means of a conduit 4.0 configured for this purpose, for example. The microwave generating device 4 may comprise a magnetron, and it may be arranged in the second station 102 in a fixed manner. If it is the cover 2 that moves to generate the previously described seal, then it is the conduit 4.0 that communicates the microwave generation device 4 with the through hole 2.0 that moves (said conduit 4.0 being flexible then).

The installation 1000 comprises a suction plate 3, preferably attached to the cover 2 with freedom of vertical movement, and which, when the work box 1 is in the second station 102, is arranged between said cover 2 and the platform 1.1 of said working box 1, and the current generation device 5 is configured to apply a suction on the interior space 1.0 through the suction plate 3 and the cover 2. As described with respect to the suction plate 3 for the The method is also valid for installation 1000, in any of its embodiments and / or configurations, and is not explained again for said installation 1000.

The connection between the suction plate 3 and the cover 2 can be made, for example, by means of a column 2.2, and the suction plate 3 can be displaced with respect to said column 2.2.

The current generation device 5 is configured to apply suction through said suction plate 3, as described for the method. Furthermore, in a preferred embodiment, the current generation device 5 is arranged outside the interior space 1.0 after sealing it, and communicates with the cover 2 through a conduit 5.0 specific for this purpose. The cover 2 also comprises a through hole 2.1 communicated with said current generation device 5, to allow the generation of suction through the suction plate 3. Furthermore, the column 2.2 is partially hollow and is communicated with the through hole 2.1 (preferably it is aligned with said through hole 2.1), and the suction zone 3.0 is communicated with said column 2.2 (with the gap of column 2.2), in such a way that the suction generated from the current generation device 5 reaches up to the interior space 1.0 delimited by work box 1.

As described for the method, in a preferred embodiment devices 4 and 5 do not interfere under said work box 1. In said preferred embodiment the second station 102 of the installation 1000 comprises a cleaning platform 102.0, which is arranged on a frame 102.1 of the second station 102, and the work box 1 and the cleaning platform 102.0 are configured to be coupled to each other. The platform 1.1 of the work box 1 comprises a plurality of evacuation holes 1.1a with controlled opening, as described for the method (explanation also valid for installation 1000), through which the granulated material can be evacuated of the interior space 1.0 of the work box 1. The cleaning platform 102.0 comprises a frame that is attached to the work box 1, and is hollow (or partially hollow), allowing the excess granulated material to be evacuated of the work box 1 through the evacuation holes 1.1a of the platform 1.1 falls through, and can be collected for later transport to where it is required (to dispose of it or even to reuse it if possible).

In said preferred embodiment, the platform 1.1 is formed by a plurality of parallel plates 1.10, preferably three, arranged one above the other like a sandwich. Each plate 1.1b comprises a plurality of through holes 1.11, and to open the holes 1.1a of the platform 1.1 the displacement of at least one of said plates 1.10 is caused, in a transverse direction T, in such a way that the holes 1.11 of the different plates 1.10 are aligned and allow the passage of the non-solidified binder material through the platform 1.1, as shown by way of example in figure 7b. In this way, when the holes 1.11 of the different plates 1.10 are aligned, the holes 1.1a are said to be open, since the non-solidified granular material is allowed to pass through them out of the work box 1.

As described for the method, the cleaning platform 102.0 is supported on a plurality of support areas that can be moved in height in a controllable and independent manner, with the controlled movement of said support areas generating a controlled inclination of the work box 1 in different directions, as shown by way of example in figure 8. The cleaning platform 102.0 preferably comprises a rectangular base (in the preferred embodiment, as described for the method), said cleaning platform 102.0 being supported on four support zones and each support zone being close to, or under, one of the vertices of the cleaning platform 102.0.

The second station 102 comprises a plurality of inflatable elements 102.2 arranged between the structure 102.1 and the cleaning platform 102.0, each inflatable element 102.2 comprising at least one of the support areas on which the cleaning platform 102.0 rests, said elements being inflatables 102.2 configured to be controlled independently, inflating and deflating in a controlled manner to cause vertical displacement of the corresponding support zone.

For cleaning, the installation may comprise a device for generating vibrations (not represented in the figures) to cause a vibration of the work box 1, to remove the non-solidified granulated material. Said device can be used alone, or in combination with the means for tilting the work box 1. The installation 1000 according to the invention is configured to be able to implement the method according to the invention, in any of its embodiments and / or configurations, and vice versa. Thus, the facility 1000 will comprise the configuration necessary to implement the required configuration or embodiment of the method, and vice versa. What is described with respect to the method is thus also valid for the corresponding embodiments / configurations of the installation 1000, and what is described with respect to the installation 1000 is thus also valid for the corresponding embodiments / configurations of the method.

Claims (12)

1. Method for the manufacture of sand cores, which comprises a generation stage in which at least one core (9) with the desired shape is generated in an interior space (1.0) delimited by a work box (1), by 3D manufacturing in which a plurality of layers of a granulated material and an additive that solidifies the granulated material are applied alternately and selectively on a platform (1.1) of the work box (1), and a hardening step in which the male (9) generated in the generation stage is hardened, the generation stage being implemented with the work box (1) in a first station (101) of a facility (1000) and the hardening stage being implemented in a second station (102) of said installation (1000), the work box (1) being transported to the second station (102) where the hardening stage is implemented, after executing the generation stage in the first station (101) , characterized in that in the stage a of hardening, to harden the male (9) generated in the generation stage, microwaves and a drying current are applied in the interior space (1.0) of the work box (1) where said male (9) is arranged, and in said hardening stage, before the application of microwaves and the drying current, the interior space (1.0) of the work box (1) is sealed at the top, with a lid (2) configured for this purpose, causing the vertical displacement of the cover (2) towards the work box (1) or of the work box (1) towards the cover (2) to carry out the hermetic closure, generating the drying current by applying a suction on the interior space (1.0) of the work box (1), from the outside of said interior space (1.0), said suction being applied through a suction plate (3) that is arranged between the cover (2 ) and the material present in the interior space (1.0) of the work box (1), and with said plate suction (3) in contact with said material. Method according to claim 1, wherein the microwaves are applied from outside the interior space (1.0) of the working box (1) and through the cover (2), said cover (2) comprising at least one hole through (2.0) through which the microwaves are directed towards the interior space (1.0) of the work box (1). 3. Method according to claim 1 or 2, wherein the suction is generated from above the interior space (1.0) of the working box (1), through the lid (2) and the suction plate (3) attached to said cover (2), the platform (1.1) comprising, in at least one suction zone, a certain porosity that allows the passage of air through it, but not the passage of granulated material. 4. Method according to claim 3, wherein the suction plate (3) comprises, at least in a suction zone (3.0), a determined porosity that allows the passage of air through it, but not the passage of material. granulate, applying suction through said suction zone (3.0). Method according to claim 3 or 4, wherein the work box (1) is coupled to a structure (102.1) of the second station (102) and the hardening step is implemented in said second station (102) with the box (1) coupled to said structure (102.1), the method comprising a cleaning stage after the hardening stage, which is implemented with the working box (1) in the second station (102) and in which the separates the excess granulated material from the core (9) and said excess granulated material is evacuated from the interior space (1.0) of said work box (1) through the platform (1.1) of said work box (1). Method according to claim 5, wherein the platform (1.1) of the work box (1) comprises a plurality of evacuation holes (1.1a) to evacuate the excess granulated material from the interior space (1.0) of the the work box (1), which are opened in a controlled manner in the cleaning stage to allow said evacuation, the structure (102.1) of the second station (102) comprising a cleaning platform (102.0) on which it is arranged, and to which it is coupled, the work box (1) when said work box (1) is coupled to said structure (102.1). 7. Installation configured for the manufacture of sand cores, the installation (1000) comprising a work box (1) where at least one core (9) is generated and comprising a platform (1.1), a first station (101) configured to house the work box (1), manufacturing means that are associated with the first station (101) and that are configured to generate the cores (9) in an interior space (1.0) delimited by the work box ( 1), by means of 3D manufacturing in which a plurality of layers of a granulated material and an additive that solidifies the granulated material are applied alternately and selectively, on the platform (1.1) of said work box (1), a second station (102) configured to receive the work box (1), a transport device to move the work box (1) from the first station (101) to the second station (102), and a hardening means that are associated with the second station (102) and are configured to harden the cores (9) generated in the first station (101), characterized in that the hardening means comprise at least one microwave generation device (4) and to apply them to the interior space (1.0) delimited by the work box (1), when said working box (1) is in the second station (102), and a current generation device (5) configured to generate a drying current in said interior space (1.0), when said box of work station (1) is in the second station (102), the installation (1000) also comprising, in the second station (102), a cover (2) configured to close the interior space (1.0) of the work box (1 ) tightly on the side upper part thereof, movement means to move the lid (2) or the work box (1) vertically to establish said tight closure and a suction plate (3) attached to the lid (2) with freedom of vertical movement, and, when the work box (1) is in the second station (102), said suction plate (3) is arranged between said lid (2) and the platform (1.1) of said work box (1), and the current generating device (5) being configured to apply a suction in the interior space (1.0) through the suction plate (3) and the cover (2) to generate the drying current. 8. Installation according to claim 7, wherein the microwave generation device (4) is attached to the cover (2) and communicated with at least one through hole (2.0) of said cover (2), in such a way that the The microwaves that it generates reach the interior space (1.0) of the work box (1) through said through holes (2.0) of the cover (2), said cover (2) preferably comprising a material adapted to support the microwaves . Installation according to claim 7 or 8, wherein the current generation device (5) is in communication with said suction plate (3) through the cover (2) and is configured to apply suction from above the space inside (1.0) and through the cover (2) and said suction plate (3). 10. Installation according to claim 9, wherein the suction plate (3) is attached to the cover (2) by means of a hollow column (2.2), the cover (2) comprising a through hole (2.1) communicated with the hollow of the column (2.2) and said hole being communicated with the suction plate (3), the current generation device (5) being communicated with the through hole (2.1) of the cover (2), in such a way that it is communicated with the suction plate (3) through said through hole (2.1) and the hole in the column (2.2). Installation according to claim 8 or 9, wherein the suction plate (3) comprises, at least in a suction zone (3.0), a certain porosity that allows air to pass through it, but not the passage of granulated material, and the cover (2) comprises at least one through hole (2.0) communicated with the current generation device (5) and with said suction zone (3.0). 12. Installation according to any one of claims 7 to 11, wherein the second station (102) comprises a structure (102.1) with a cleaning platform (102.0), the work box (1) and the cleaning platform (102.0) being ) configured to allow a coupling between them, to generate the drying current, the platform (1.1) comprising a plurality of evacuation holes (1.1a) with controlled opening, through which the excess granulated material from the space can be evacuated inside (1.0) of the work box (1) and the installation (1000) comprising, in the second station (102), means to generate said opening.